The problem is that we host another domain name and some of our desktop email is supposed to go out as [email protected], and in fact if the email client was setup correctly on the workstations, the email did go out as from [email protected] but now they all go out as [email protected]

How can I set it up so that the domain name the email client on the LAN workstations uses is the one that gets used on the outgoing mail ? Or to put another way, how can I set it up so that only the @net.ourpc.org of any outgoing email gets changed to @ourpc.org ?